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Commit 1a34c064 authored by Dan Williams's avatar Dan Williams Committed by James Bottomley
Browse files

[SCSI] libsas: fix port->dev_list locking 

port->dev_list maintains a list of devices attached to a given sas root port.
It needs to be mutated under a lock as contexts outside of the
single-threaded-libsas-workqueue access the list via sas_find_dev_by_rphy().
Fixup locations where the list was being mutated without a lock.

This is a follow-up to commit 5911e963 "[SCSI] libsas: remove expander
from dev list on error", where Luben noted [1]:

    > 2/ We have unlocked list manipulations in sas_ex_discover_end_dev(),
    > sas_unregister_common_dev(), and sas_ex_discover_end_dev()

    Yes, I can see that and that is very unfortunate.

[1]: http://marc.info/?l=linux-scsi&m=131480962006471&w=2



Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent 29f366e8

drivers/scsi/libsas/sas_discover.c

+8 −5
Original line number Diff line number Diff line
@@ -219,17 +219,20 @@ int sas_discover_end_dev(struct domain_device *dev) 


/* ---------- Device registration and unregistration ---------- */



static inline void sas_unregister_common_dev(struct domain_device *dev)

static void sas_unregister_common_dev(struct asd_sas_port *port, struct domain_device *dev)

{

	sas_notify_lldd_dev_gone(dev);

	if (!dev->parent)

		dev->port->port_dev = NULL;

	else

		list_del_init(&dev->siblings);



	spin_lock_irq(&port->dev_list_lock);

	list_del_init(&dev->dev_list_node);

	spin_unlock_irq(&port->dev_list_lock);

}



void sas_unregister_dev(struct domain_device *dev)

void sas_unregister_dev(struct asd_sas_port *port, struct domain_device *dev)

{

	if (dev->rphy) {

		sas_remove_children(&dev->rphy->dev);
@@ -241,7 +244,7 @@ void sas_unregister_dev(struct domain_device *dev) 
		kfree(dev->ex_dev.ex_phy);

		dev->ex_dev.ex_phy = NULL;

	}

	sas_unregister_common_dev(dev);

	sas_unregister_common_dev(port, dev);

}



void sas_unregister_domain_devices(struct asd_sas_port *port)
@@ -249,7 +252,7 @@ void sas_unregister_domain_devices(struct asd_sas_port *port) 
	struct domain_device *dev, *n;



	list_for_each_entry_safe_reverse(dev, n, &port->dev_list, dev_list_node)

		sas_unregister_dev(dev);

		sas_unregister_dev(port, dev);



	port->port->rphy = NULL;

drivers/scsi/libsas/sas_expander.c

+9 −6
Original line number Diff line number Diff line
@@ -754,7 +754,10 @@ static struct domain_device *sas_ex_discover_end_dev( 
 out_list_del:

	sas_rphy_free(child->rphy);

	child->rphy = NULL;



	spin_lock_irq(&parent->port->dev_list_lock);

	list_del(&child->dev_list_node);

	spin_unlock_irq(&parent->port->dev_list_lock);

 out_free:

	sas_port_delete(phy->port);

 out_err:
@@ -1739,7 +1742,7 @@ static int sas_find_bcast_dev(struct domain_device *dev, 
	return res;

}



static void sas_unregister_ex_tree(struct domain_device *dev)

static void sas_unregister_ex_tree(struct asd_sas_port *port, struct domain_device *dev)

{

	struct expander_device *ex = &dev->ex_dev;

	struct domain_device *child, *n;
@@ -1748,11 +1751,11 @@ static void sas_unregister_ex_tree(struct domain_device *dev) 
		child->gone = 1;

		if (child->dev_type == EDGE_DEV ||

		    child->dev_type == FANOUT_DEV)

			sas_unregister_ex_tree(child);

			sas_unregister_ex_tree(port, child);

		else

			sas_unregister_dev(child);

			sas_unregister_dev(port, child);

	}

	sas_unregister_dev(dev);

	sas_unregister_dev(port, dev);

}



static void sas_unregister_devs_sas_addr(struct domain_device *parent,
@@ -1769,9 +1772,9 @@ static void sas_unregister_devs_sas_addr(struct domain_device *parent, 
				child->gone = 1;

				if (child->dev_type == EDGE_DEV ||

				    child->dev_type == FANOUT_DEV)

					sas_unregister_ex_tree(child);

					sas_unregister_ex_tree(parent->port, child);

				else

					sas_unregister_dev(child);

					sas_unregister_dev(parent->port, child);

				break;

			}

		}

include/scsi/libsas.h

+1 −1
Original line number Diff line number Diff line
@@ -656,7 +656,7 @@ int sas_discover_event(struct asd_sas_port *, enum discover_event ev); 
int  sas_discover_sata(struct domain_device *);

int  sas_discover_end_dev(struct domain_device *);



void sas_unregister_dev(struct domain_device *);

void sas_unregister_dev(struct asd_sas_port *port, struct domain_device *);



void sas_init_dev(struct domain_device *);